Silkyara tunnel collapse | On Day 15, rescuers set a 100-hour vertical drilling target

The attention of the authorities shifted to vertical boring when plans to restart the horizontal drilling process yet again failed; 19.5 metres of vertical boring completed on first day; rescuers need to drill through 86 metres of mountain

A vertical drilling machine is taken to the mountain top at the Silkyara tunnel site as the operation to rescue 41 trapped workers continues in Uttarakhand’s Uttarkashi district on November 26, 2023. | Photo Credit: Shashi Shekhar Kashyap

With horizontal drilling to reach the 41 workers trapped in the Silkyara tunnel stuck for the third consecutive day, rescuers began vertical drilling above the tunnel, completing nearly 19.5 meters of boring on November 26. The teams have set a target of vertically drilling through 86 metres of mountain in 100 hours, if there are no unexpected hurdles.

Briefing the media about the vertical drilling, as the rescue operation entered its 15th day, Additional Secretary (Technical, Road and Transport) Mahmood Ahmed said there could be a need to change the “needle” or head of the drilling machine after a point of time and necessary arrangements for the same are already in place.

“We should not give targets any more but at the pace with which vertical drilling is going on, I can say we will complete it in 100 hours if no hurdle comes our way,” he added.

One of the rescuers told The Hindu that “the initial few metres will be easier to drill but it will be a challenge when the drilling machine hits the crust [outermost part] of the tunnel”. If this process is completed smoothly, the workers will be taken out in buckets through the vertical hole being bored, he said.

The attention of the authorities shifted to vertical boring when plans to restart the horizontal drilling process yet again failed, with workers struggling to retrieve the broken parts of American Auger machine, which is stuck amid the pipes since Friday night. When the machine is completely extricated, rescuers are likely to commence manual horizontal drilling to reach the workers, who are trapped behind 10-12 metres of debris.

Hopes and despair as rescue efforts continue at Uttarkashi | In pictures

An under construction tunnel collapsed in the district of Uttarkashi on November 20, 2023, trapping 41 workers inside. In an effort to bring the trapped labourers, many methods are being employed.

Workers work inside the tunnel after a portion of the tunnel collapsed. The tunnel is being constructed under the National Highways and Infrastructure Development Corporation Limited (NHIDCL), on November 19, 2023.

A high-performance drilling machine is being brought for the rescue operation. In total, five different approaches to the workers are being explored simultaneously, on top of the auger machine at the southern entrance. Heavy machinery and concrete blocks were being trucked into the site throughout the day, on November 19, 2023.

New machines near the tunnel. The first machine of Satluj Jal Vidyut Nigam (SJVN) for the construction of the vertical rescue tunnel has already reached the site and operations are being commenced post completion of access road by the Border Roads Organisation (BRO). Movement of two other machines for the vertical tunnel construction started from Gujarat and Odisha by road, on November 20, 2023.

Workers clean extra food bottles that are brought back from the tunnel under rescue operation. The workers are safe and have asked for food, which is being sent to them, the Silkyara police control room said, adding that communication has been established on walkie-talkies. Food packets have been supplied with the help of compressors, it said, on November 20, 2023.

Pipes, machines and slabs are being brought for the rescue operation. In a first major breakthrough in nine days, agencies working round the clock to rescue the 41 workers trapped in an under-construction tunnel at Silkyara in Uttarkashi district of Uttarakhand have managed to install a six-inch pipe into the 53-metre-long debris on November 20, 2023.

Prayers are being offered by different pandits next to the tunnel. The government is sending multivitamins, antidepressants and dry fruits to 41 workers trapped for the past seven days in an under-construction tunnel that collapsed in the Uttarkashi district of Uttarakhand, Road, Transport and Highways Secretary Anurag Jain said, on November 20, 2023.

Arnold Dix, President , International Tunnelling and Underground Space Association, from Australia, inspects the vertical drilling on top of the mountain face below which the under construction tunnel collapsed, on November 20, 2023.

Wife (Rajni) of a trapped worker (Birender Kisku) from Banka, Bihar, gestures near a temporary police help desk near the Uttarkashi Tunnel Collapse site. 41 workers have been trapped since Nov. 12 morning at the partially collapsed Silkyara tunnel.

Workers stand on top of the mountain face below which the under construction tunnel collapsed, on November 20, 2023.

Workers make road for the vertical drilling on top of the mountain face. Rescue workers at the collapsed tunnel in Uttarkashi started exploring other ways to reach workers, including from the top of the mountain face through which the tunnel is being constructed, officials announced on Saturday. The longer 170 metre route from the top, running simultaneously with other approaches, may take far longer to bore through than the approximately 60 metres of rubble at the southern entrance, on November 18, 2023.

NDRF at the spot from where vertical drilling will start on the mountain face. About 160 personnel of agencies such as the National Disaster Response Force (NDRF), State Disaster Response Force (SDRF), Indo-Tibetan Border Police (ITBP) and the Border Roads Organisation (BRO) are trying to rescue the trapped labourers, on November 17, 2023.

A help desk has been installed near the tunnel collapse site, to help the families of the workers trapped inside the under-construction tunnel, on November 19, 2023.

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Meanwhile, the Indian Army too has stepped into the rescue operation. In Delhi, National Disaster Management Authority (NDMA) member Lieutenant-General Syed Ata Hasnain informed that a unit of Madras Sappers, part of the Corps of Engineers of the Army, will now help in the operations.

“For manual drilling, the Indian Army along with other rescuers will do rat boring inside the tunnel. They will dig out the debris from inside the tunnel with hands, hammers and chisels and then a pipe will be pushed forward from the platform built inside the pipe,” he added.

In another challenge for the rescue teams, the India Meteorological Department has predicted snowfall and rainfall in Uttarkashi district on Monday, which is located at an altitude of 3,500m above sea level. The weather conditions will further complicate the operation for the rescuers who are already braving difficult conditions including hilly terrain.

The NDMA and SDRF officials say that arrangements have been made to tackle the worsening weather though there are fears that rainfall will hamper the work.

The NDMA member also added that horizontal drilling from another point, the Barkot side of the tunnel, also moved a little on Sunday with rescue teams covering a little over 10 metres after the fifth blast. The perpendicular drilling by the RVNL is yet to start but machines for the same are on the way.

The Tehri and Uttarkashi Police, late on Saturday night had created a green corridor to transport the plasma cutter machine being flown from Hyderabad to the rescue site. The plasma cutter was used, along with gas cutter, to manually dismantle the parts of damaged blades of the Auger machine.

For the uninitiated, on November 12, a portion of the under-construction Silkyara-Barkot tunnel in Uttarakhand collapsed, trapping 41 labourers behind 60 metres of debris. The area of entrapment, measuring 8.5 meters in height and two kilometres in length, is the built-up portion of the tunnel, offering safety to the labours with electricity and water supply available. Food is being provided to the men as rescuers had managed to push a six-inch diameter pipe through the debris inside the tunnel.

Initially, authorities opted to insert a 900-mm pipe through the debris, but safety concerns led to the exploration of multiple rescue options simultaneously.